The present invention relates to a process condition detector for detecting a condition of a process, particularly to a process condition detector for detecting a change in aging and accuracy of a sensor which measures a condition of a process and predicts the service life of the sensor.
A conventional process condition detector apparatus is provided with a main sensor (e.g., differential pressure sensor) for measuring a specific condition of a process and a compensation sensor (e.g., static pressure sensor or temperature sensor) for measuring other conditions of the process on a semiconductor sensor substrate in order to precisely detect the process condition. The relationship between the output characteristic of the main sensor and that of the compensation sensor is preliminarily found before detecting actual plant data. Thus, the process condition of a process is precisely detected by correcting the output of the main sensor with that of the compensation sensor when the actual process data is measured.
When measuring a condition of an actual process, the conventional detecting apparatus is normally disposed in the field where the process is performed. Disposing the conventional detecting apparatus in the field subjects a semiconductor sensor of the apparatus to greatly varying conditions in the field caused by the process. Thus, the characteristics of the main sensor and the compensation sensor for detecting the process condition change as time passes. Particularly the conventional detecting apparatus becomes less accurate as time passes.
The conventional detecting apparatus does not have any means for detecting the change in the characteristics of the main and compensating sensors with the passage of time. Thus, the output of the conventional detecting apparatus for the same process condition changes with the passage of time. Therefore, a critical problem may occur in process operation because the process condition detected by the conventional detecting apparatus becomes more and more different from the actual process condition as time passes.